Accrued Expenses And Other Current Liabilities (Schedule Of Reconciliation Of The Activity Related To Accrued Warranty) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance at beginning of period	$ 38,502	$ 32,393
Provision for warranty expense	23,512	18,570
Warranty liability from acquired businesses	782	150
Warranty costs paid	(17,466)	(13,963)
Balance at end of period	45,330	37,150
Less long-term portion	17,979	13,592
Current portion of accrued warranty	$ 27,351	$ 23,558	$ 23,055